Device for limiting rotary motion



Oct. 20, 1953 w, BEHRENS 2,655,811

DEVICE FOR LIMITING ROTARY MOTION Filed Feb. 16, 1952 2 Sheets-Sheet 1IN VEN TOR. m; L AM If. 17105:

Oct. 20, 1953 w. H. BEHRENS DEVICE FOR LIMITING ROTARY MOTION 2Sheets-Sheet 2 Filed Feb. 16, 1952 Arramvrr Patented Oct. 20, 1953 I2.655.811 DEVICE FOR LIMITING ROTARY MOTION William H. Behrens,Postville, Iowa, assignor to Collins Radio Company, Cedar Rapids, Iowa,a corporation of Iowa Application February 16, 1952, Serial No. 271,965

4 Claims.

This. invention relates in general to motion limiting means and inparticular to a pair of rotatably supported dials wherein the limits ofrotation of one of the dials are varied in accordance with the positionof the other dial.

It is oftentimes desirable to mount a pair of concentric dials so thatone dial indicates a portion of the setting and the other dial indicatesthe remaining portion of the setting. Suppose, for example, that in aradio receiver it is desired to cover the tuning range from 40.6 to 46.9megacycles. If the outer dial is calibrated from 40 to 46 megacycles,rotation of it would automatically set up the megacycle position. Toobtain the one-tenth setting a second dial may be mounted concentricwith the first dial and calibrated from zero to nine. However, if it isdesired to remain in the 40.6 to the 54.9-range, means must be providedso that when the outer dial is in the 40 megacycle position the innerdial will not go below six. When the outer dial is moved to 41megacycles or any other setting, the inner dial must be free to moveover the entire range.

It is an object of this invention therefore, to I provide a motionlimiting device.

Another object of this invention is to provide a pair of improvedcontrol dials.

Further objects, features and advantages of this invention will becomeapparent from the following description and claims when read in view ofthe drawings, in which:

Figure l is a disassembled view showing the relative space relationshipof the various parts;

Figure 2 is a top view of the control device of this invention with theinner dial in the locked position;

Figure 3 is a top view of this device with the inner dial in theunlocked position;

Figure 4 is a sectional view illustrating the device in the lockedposition;

Figure 5 is a sectional view illustrating the device in the unlockedposition,

Figure 6 is a front view of the device, and;

Figure '7 is an enlarged detail view of the spring 25.

Figure 1 illustrates an indicator dial l0 which is formed with an outerknurled edge II and which has a center sleeve portion [2 that isconnected to the outer portion by an extension IS.

A second indicator dial I4 is formed with an internal opening [6 of asize just large enough to fit over the portion 12 and has an outsidediameter just small enough to fit within a circular opening 11 formed inthe member H]. A handle 18 is attached to the member I4. A generallyarcuate slot i9 is formed in the member [4 and a central opening 2| isformed substantially through the member [4. A link member 22 has apivotopening 23 formed at one end and a locking pin 24 is attached to theother end.

As best shown in Figure 2, the members I0, 14 and 22 are assembledtogether and mounted 'on a base plate 26. The link member 22 ispivotally supported on the base plate 26 by a pin 21 that passes throughthe opening 23. A spring 25 biases the link 22 away from the center ofmember ID.

A hollow shaft 28 passes through an opening formed in the plate 26 andis attached to the portion I2 by a set screw 29 receivable in an Opening3|. This is best shown in Figure 4.

A second shaft 32 is rotatably mounted within the hollow shaft 28 andhas its end connected to the member l4 bya set screw 33.

The member H! has a portion 34 which has cam portions 36 and 31 ateither end thereof.

The cam portion 36 is adaptable to engage the pin 24 and cam it into theopening ll. This cannot be accomplished, however, unless the opening iiiof the member I4 is adjacent the pin 24. When this occurs, the pin 24may move within the confines of the opening l9 and will limit themovement of the member l4 an amount equal to the angle of the openingl9.

Figures 2 and 4 illustrate the top view and a sectional view of thelocked position with the pin 24 in the opening l9.

Figures 3 and 5 illustrate the unlocked position wherein the member I4is free to rotate as desired.

The indicator dial l6 might, for example, be calibrated from 40-46 asshown in Figures 2 and 3 and the dial I4 may be calibrated from 0.1 to0.9. Suppose, for example, that it is desired to tune from 40.6 to 46.9.The inner dial l4 must be able to rotate over the entire range from 1 to9 for every position of the dial I0 except the one corresponding to 40.When the dial [0 is set to 40, inner dial l4 must be locked so that itwill not move below 6. The present apparatus prevents the outer dial infrom being moved into the 40 setting unless a unit larger than 5 isadjacent the Pin 24.

The spring biasing means 25 urges the link 22 outwardly from the dial l4so that it is cammed into engagement with the dial l4 only when itengages the cam portions 36 and 31.

It is to be realized that the upper as well as the lower unit may beregulated and an example of a lower limit is given for illustrativepurposes only.

Although this invention has been described with respect to a particularembodiment thereof, it is not to be so limited as changes andmodifications may be made therein which are within the full intendedscope of the invention as defined by the appended claims.

I claim: V

1. Apparatus for limiting the relative motion between a pair of dialscomprising, an outer dial, an inner dial, a generally arcuate slotformed in the inner dial, cam means formed in the outer dial, a baseplate, a first hollow .shaft rotataabl supported by said base plate andattached to said outer dial, a shaft received with-insaid hol low shaftand attached to said inner dial, a link member pivotally supported onsaid plate, a locking pin attached to said member and-extendingtransversely thereof betweenuthe .outer and inner dials, and saidlocking pin engageable with the cam portion of the outer dial.

'2. Motion limiting means comprising outer and inner dials, a firsthollow shaft attached to the outer dial, a second shaft passingrotatably through the second shaft and attached to the inner dial, aplate rotatably supporting the first and second shafts, a link memberpivotally supported on said plate, a generally arcuate opening formed insaid outer dial with cam surfaces formed at either end thereof, anarcuate slot formed in the inner dial, and a locking pin attached tosaid link member and received in said arcuate opening and into-the saidarcuate slo to limit the motion of the inner dial.

3.- Motion limiting apparatus for a pair of dia mounted concentricallywith respect to each other comprising, a plate, an outer and innerdial-,a first hollow shaft rotatably supported by said plate andattached to said outer dial, a second shaft rotatably supported withinsaid hollow shaft and attached to said inner dial, a generally crescentshaped opening formed in said outer dial, a link member pivotallysupported by said plate, a locking pin attached to one end of said linkmember and received in said crescent shaped opening, and a locking slotformed in said inner dial and engageable with saidiqlqcking pin when itis cammed into the end position by said outer dial 4. A motion limitingmeans for limiting the motion ;ofan 'innemdial with respect to an outerdial when the outer dial is in a certain positioncomprising-aninnerdial, an outer dial, a plate,

'ahhollow shaft rotatably supported by said plate,

said outer dial connected to said hollow shaft, asecond shafttreceivedthrough said hollow shaft and connected to said inner dial, a circularopening formed substantially through said outer dial and said inner dialreceived therein, a center sleeve portion attached to said outerdiaLalink member pivotally supported by said plate, and received withinthe confines of said outer dial. spring biasing means normally biasingsaid link member radially outward from said inner dial, a cam portionformed on said outer dial and engageable with said link member to cam itin toward said inner dial, and said inner dial formed with an arcuateslotinto which the link member is received'whencammed therein.

I-I. BEHRENS.

Number Name Date K 1,599,548 Baggott, .Septnll, 1926 Butler Sept. 3,1929

